Lateral variation of target poisoning during reactive magnetron sputtering

The reactive gas incorporation into a Ti sputter target has been investigated using laterally resolving ion beam analysis during dc magnetron deposition of TiN in an Ar∕N2 atmosphere. At sufficiently low reactive gas flow, the nitrogen incorporation exhibits a pronounced lateral variation, with a lower areal density in the target racetrack compared to the target center and edge. The findings are reproduced by model calculations. In the racetrack, the balance of reactive gas injection and sputter erosion is shifted toward erosion. The injection of nitrogen is dominated by combined molecular adsorption and recoil implantation versus direct ion implantation.